Hello a friend of mine was running his Craftsman rider 26 hp B&S engine in the shed and out of no where ( No knocking or anything )it lost valve timing it stopped running with compression leaking out the exhaust, is this a major repair, now it cranks over vary easy with no abnormal sounds just compression out the exhaust, my ?? is he said I could have it ,it is a nice mower but is it fixable or worth it .. Thanks Bryan
- Thread starter herk
- Start date
old
Well-known Member
- Location
- Camdenton Missouri
Over head valve engine or valve in the block?? Not common to loose timing but common to have odd valve problems with over head valve engines
Janicholson
Well-known Member
Stuck valve is likely the cause. If OHV, removing the rocker and removing the valve spring (Easy with groove joint pliers)the valve can be lubricated with Blaster or?, then rotated a=pushed and pulled till free. I have used a hand cranked hand drill to spin the valve while pushing in and out to get juice in the guide. Then use engine oil on it to make the lube last. Reassemble and there it is. In the bock can be done but requires the head removal. Jim
used red MN
Well-known Member
- Location
- Coon Rapids, MN
Do others know if these engines have steel valve seats? Sometimes the valve in block Briggs engines would have a seat come out. Not sure if that happened on an OHV model if it would make the valve hit the piston if the seat was out and holding the valve open.
caterpillar guy
Well-known Member
A BS engine. Best use of them is with a big washer on the end of the crank tie a rope on. The other end tie it to a boat and throw over will hold fine till you want to come in. Just cut rope.
Traditional Farmer
Well-known Member
- Location
- Virginia
X2
cole in mo
Member
Most likley the timing gear went out, if nothing else is damaged, it's a simple fix.
Gene Davis (Ga.)
Well-known Member
Sometimes the V-Twin Briggs will have a push rod to bend, the intake push rod is aluminum and if that is the case the exhaust valve push rod is steel and can be used in both places. The valve clearance is only .004 on these and is set with the # 1 piston 1/4 past TDC to get the compression relief correct.
Determined
Well-known Member
While not terribly common I have personally seen it several times where a screw from the choke or throttle plate has worked loose and ended up stuck holding a valve open.
Only takes a flashlight and a few minutes to check to see if they are still in place.
Only takes a flashlight and a few minutes to check to see if they are still in place.
560Dennis
Well-known Member
- Location
- Madison,Ohio
Been 20 years or more ,but I had intec valve issues with the rockers (nut) loosen up . Push rods were out . So what every body said. I suggest take the valve covers off and inspection of what happened.
Dont remember what to fix it to long ago . Might have use use thread lockers
Dont remember what to fix it to long ago . Might have use use thread lockers
Billy Shafer
Well-known Member
That problem is more common than people know. I have seen it many
times on Onan units. Most of the time no real damage is done. I would
check thar first. Before you dig into it.
times on Onan units. Most of the time no real damage is done. I would
check thar first. Before you dig into it.
Steve@Advance
Well-known Member
Diagnose first.
Take the valve covers off, then you can check for tight adjustments, stuck valves, bent pushrods, and check the valve timing without going into the bottom end.
I'm thinking some of those had a plastic cam gear. One thing for sure, it didn't jump time without a reason. If it's out of time, something had to break.
Take the valve covers off, then you can check for tight adjustments, stuck valves, bent pushrods, and check the valve timing without going into the bottom end.
I'm thinking some of those had a plastic cam gear. One thing for sure, it didn't jump time without a reason. If it's out of time, something had to break.
Goose
Well-known Member
I have a rider with a 24hp Briggs engine.
A couple of years ago, it started bending pushrods, giving similar symptoms. I mentioned it on this site and someone said to use Mobil 1 synthetic oil.
I found some steel tubing that was an exact press fit over the pushrods. I put a sleeve of the steel tubing over every pushrod and started using Mobil 1 in it. so far, no more problems. I really can't say how much the Mobil 1 helps.
A couple of years ago, it started bending pushrods, giving similar symptoms. I mentioned it on this site and someone said to use Mobil 1 synthetic oil.
I found some steel tubing that was an exact press fit over the pushrods. I put a sleeve of the steel tubing over every pushrod and started using Mobil 1 in it. so far, no more problems. I really can't say how much the Mobil 1 helps.
Fritz Maurer
Well-known Member
Innuendo doesnt help anyone fix anything.
Carlmac 369
Member
????
Tracy Brown
Member
A B&S engine is not what it used to be. I bought a new Kubota zero turn with a 24 HP B&S. I would buy another Kubota but it won't have a B&S on it.
Being 26 hp. I am thinking it is a twin cylinder engine.
Remove the valve covers. Crank the engine over and observe their operation.
Something like 3 years ago, Briggs decided to switch their engines to 'laminated' or built-up camshafts. The cam gear and the cam lobes are pressed onto a shaft. I have replaced many of these camshafts in their single cylinder engines and so far have seen two of their twin cylinder engines with a failed camshaft.
The single cylinder engines tend to break the compression release off and then they won't start. The starter can't crank against full engine compression.
On both the twin cylinder engines the cam gear broke apart and the valves were not moving.
Remove the valve covers. Crank the engine over and observe their operation.
Something like 3 years ago, Briggs decided to switch their engines to 'laminated' or built-up camshafts. The cam gear and the cam lobes are pressed onto a shaft. I have replaced many of these camshafts in their single cylinder engines and so far have seen two of their twin cylinder engines with a failed camshaft.
The single cylinder engines tend to break the compression release off and then they won't start. The starter can't crank against full engine compression.
On both the twin cylinder engines the cam gear broke apart and the valves were not moving.
Carlmac 369
Member
Good info there. I'll keep that in mind.
stevieb49829
Well-known Member
- Location
- Spirit Lake, Idaho
I second the valve seat coming out. Happened to me on a 16 hp. Pulled the head and there it was, cocked to one side under the valve head. Didn't think it would be worth the price of fixing it.
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